A Linked Data application might apply the Follow Your Nose pattern to discover additional data about resources in an RDF graph. But the application may need to discover additional metadata about the dataset to which the resource belongs, such as its license. The application may also need access to additional facilities, such as a SPARQL endpoint, in order to extract any additional data it requires.

Use the Vocabulary of Interlinked Datasets (VoiD) vocabulary to publish a description of a dataset. Make this description available from the standard location at the domain of the website, i.e. /.well-known/void.

An application discovers the URI http://data.example.org/thing/1 in a dataset. De-referencing that URI will yield a description of that resource. In order to discover a SPARQL endpoint for that dataset, the application performs a GET request on http://data.example.org/.well-known/void. This URL returns a description of the dataset published at that domain.

RFC 5785 defines a means for declaring well known URIs for a website. A registry of well known URIs is maintained by the IETF, and a registration has been made for /.well-known/void. As the VoiD specification indicates, this URI should return a description of all datasets available from the specified domain.

Providing such as description allows a consuming application to bootstrap its knowledge of available datasets, their licensing, and the means of interacting with them. This can greatly simplify working with unknown data sources. For example an application could discover a SPARQL endpoint or data dump that would allow it to more efficiently harvest some required data.